To be honest, I don't really see the benefits of Silk Touch anyway. There just doesn't seem to be any really useful purpose for it.
The only benefit that I can find is that you can carry more breakable ores such as Redstone and Lapis since you can bring them back in block form. But, then you still have to re-mine them when you get them back which is just a pain.

If you're a builder, then you can get Stone from mining but I'd rather just get Cobblestone and then smelt it into Stone for XP.

So if anyone can chime in and tell me how Silk Touch is useful, I might actually find a use for these 3 pick axes I have sitting in a chest.

I think silk touch is sort of useful. Say you want a pretty, valuable ore for decoration in your house. Diamond would be pretty awesome, right? You'd be able to tell your friends you have lots of diamond and kept some. But without silk touch? You'd REALLY have to get 9 diamonds for a diamond block. Solution: Silk touch on an iron pickaxe is easy, why don't I try it on diamond ore when I go mining?
*finds diamond in cave/ravine and uses silk touch*
Oh wow no need to save up 9 DIAMONDS.

And there are plenty of other uses.
Mycelium, Grass blocks, Coal ore and plenty more.
Even furnaces that are smelting something and still on fire! (If you have time)

I don't just use it for grass blocks. I use it for mycellium blocks too. The Silk Touch enchantment is pretty much for us survivalists.

The world that I'm currently playing in is strictly Survival and I've wasted 9 diamonds (and 90 XP levels) getting Silk Touch picks one after the other. Obtaining Mycelium doesn't seem worth it to me either. I'd much rather have a good work pick with Unbreaking/Efficiency than Silk Touch. But that's probably because I just can't see any significant benefit to Silk Touch.

I got silk touch yesterday on a diamond Pickaxe, the enchantments included Unbreaking and Effiencey III. I was actually aiming for fortune but saved right after I got those three things on my second diamond pickaxe.

My friends and I use silk touch on our world for a few reasons. Between the three of us, there is usually one person with silk touch and one or two of us with an fortune III (generally with unbreaking IV and efficiency III) pick. We save the diamond ore (and others) until someone with an fortune pick can mine it. It works wonders in the nether for glowstone as well. Great for grass blocks if you need to get grass growing far away from natural grass, and for making your own mooshroom biome where you want it.

Useful for decoration purposes, too. If only you could mine ice blocks...

Its Very rare but if you want it heres a Trick you can do:
Go to enchament table
Save
click and chose echmant"longer enchmanent sentensce usally mean better"Once got 3 Unbreaking,3 Effecitnesy 1 silk touch
If not enchamnet you want exit WITHOUT Saving
Go on and do the same thing till ya get the enchament you want

I"m not a big fan of this trick. It's metagaming and borderline cheating in my view. And yeah, I've done it. I've realized my time is better spent rolling the dice than saving and reloading a hundred times. This method is extremely time consuming. Try doing this with a sword and you'll be there an hour trying to get the exact enchant you want. It's honestly a personal choice. If you want to spend your time saving and reloading a few hundred times, which what will happen as you begin to do this regularly, go for it.

Personally I've decided to not do this on my current survival world. I've found that it's totally unnecessary with even a mediocre xp farm. Perhaps I've been lucky, or perhaps since of this self imposed restriction I've been motivated to build better and better xp farms... I have a small reserve of silk touch and fortune picks. Yes these are rare, but I don't think having these on every single pick is required. MInd you, I have had my share of tools that didn't turn out as well and with the number of possible enchantments on swords, I still do not have a proper Looting III sword. That's totally ok tho... I'm almost finishing preparing the End for an Enderman farm.

Do what you want with your game time.. But I recommend that playing the game is more productive than gaming the system. After playing a world without it, I think it's not necessary. Plus I think keeping the rarity of enchantment adds to the enjoyment for me.

I think 4J would be doing a good thing if somehow they made enchanting persistent through saves, or made a mode with it. Minecraft is easy enough even on Hard already. I think metagaming sorta defeats playing on Hard. (If that's what you do.) But that's just me..